Laser resistant ceramic composite

Abstract

A hot pressed, biaxially oriented, alumina fiber reinforced, ceramic composite having alternate layers of parallel running alumina fibers within a glass matrix such that the fibers of one layer are positioned at right angles to the fibers of any adjoining layer.

What is claimed is: 
     
       1. A method for fabricating a biaxially oriented fiber reinforced, ceramic composite which comprises the steps of: a. pulling a tow of alumina having a multitude of fibers in parallel relationship to one another through an agitated organic slurry containing a suspension of finely divided glass particles comprising about 95% by weight fused silica glass and about 5% by weight borosilicate glass in order to impregnate said tow;   b. drying and cutting said impregnated tow into a sheet of predetermined shape;   c. placing layers of said sheet into a metal die such that the parallel fibers of any one sheet are laid at right angles to the parallel fibers of any adjoining sheet therefore forming a 0°, 90° biaxially oriented structure; and   d. hot pressing said layers at a temperature and pressure sufficient to form said reinforced ceramic composite.   
     
     
       2. A method in accordance with claim 1 wherein said glass slurry contains a solvent mixture of isopropyl alcohol and polyvinyl alcohol. 
     
     
       3. A method in accordance with claim 2 wherein said biaxially oriented structure is hot pressed for about one hour at a temperature of from about 1000° to 1400° C. and a pressure of from about 1000 to 4000 psi. 
     
     
       4. A method in accordance with claim 3 wherein said biaxially oriented structure is hot pressed for about one hour at a temperature of from about 1300° to 1350° C. and at a pressure of about 2000 psi. 
     
     
       5. A hot pressed, biaxially oriented, alumina fiber reinforced ceramic composite comprising at least a first and second series of alumina fibers, wherein a. said first series of alumina fibers are oriented in a parallel relationship to one another along a predetermined direction;   b. said second series of alumina fibers are juxtapositioned to said first series of fibers and are oriented in a parallel relationship to one another along a direction at right angles to that direction of said first series of fibers; and   c. a ceramic impregnant comprising about 95% by weight fused silica glass and about 5% by weight borosilicate glass permeating the interstices of said first and second series of fibers.   
     
     
       6. A hot pressed, biaxially oriented, alumina fiber reinforced ceramic composite in accordance with claim 5 further comprising a plurality of said first and second series of alumina fibers. 
     
     
       7. A hot pressed, biaxially oriented, alumina fiber reinforced ceramic composite in accordance with claim 5 wherein said alumina fibers comprise about 50 volume percent of said composite.